Gregan played in all three Tests in 2001, as the Lions slid to a 2-1 series defeat at the hands of the reigning world champions, and he expects another scintillating series.
"All of my friends are talking about it and can't believe the last tour was 12 years ago," said Gregan, who is the world record cap holder.
"Everything about the 2001 series from what happened in Brisbane, to us bouncing back in Melbourne when it was so close and the decider in Sydney - they remember it so vividly.
"It's at the back of everyone's minds again and will be on our doorstep in less than 12 months time.
"It was so tight then and came down to key moments. I expect nothing but the same this time - It will be on a knife edge."
The former scrum-half reckons the teams are evenly matched with a glittering array of talent in both sides' potential back lines and he dismissed the suggestion that the Lions could maul the Wallabies pack.
"It's hard to make a prediction so far ahead, there's a Six Nations for you guys to play and you don't know what can happen in terms of injuries. It's pretty evenly matched," said the ACT Brumbies hero.
"The brand of rugby is going to be fantastic to watch because of the personnel and attitude of both squads.
"Everyone talks about the scrum and lineout but Australia have done a lot of work on it. From that perspective there's not a lot in it.
"The backlines are also evenly matched but that makes for a great series and that's exactly what you want."
A sea of red descended on Australia in 2001 and more than 40,000 fans are again expected to make the long journey south.
And Gregan insists the Lions tour has a long-lasting, positive effect on rugby in the country.
"It has such a big impact on Australia and the Lions have a massive presence," added Gregan.
"That's not just in terms of the team but the 20,000 or more supporters they bring - they are all dressed in red, very vocal, singing all the different songs from the various parts of the UK.
"They travel with passion and wherever they go they can't help but to have a positive impact. It's one about rugby that makes it one of the best sports in the world."